150 AMPHIBIA (the frog) 



(b) The Optic Lobes lie just posterior to the cerebrum. 



(1) Shape? 



(2) Size? 



(3) Function? 



(c) The Cerebellum is posterior to the optic lobes. 



(1) Shape? 



(2) Size? 



(3) Is it convoluted, smooth, or ridged? 



(4) Use? 



(d) The Medulla Oblongata lies posterior to the cere- 



bellum. It is widest anteriorly and gradually 

 merges into the spinal cord. 



(e) For ventral view of the brain consult some good 



figure and identify the cerebral nerves. In a man 

 there are twelve pairs. How many pairs in the 

 frog? Name the pairs of cranial nerves in man 

 and state their destination and use. Same for 

 those of the frog. 



(3) The Spinal Cord. 



(a) Shape? 



(b) Length? 



(4) The Spinal Nerves. Place the frog ventral side up 



and carefully remove the viscera. In man there are 

 thirty-one pairs of spinal nerves. How many can 

 you identify coming from the spinal cord in the frog? 



(a) Are all these nerves of the same size when they leave 



the cord? 



(b) With what does the second pair (counting from the 



anterior end of the cord) unite? 



(1) What does this union then form? 



(2) What muscles does it supply? 



(c) What four other spinal nerves unite? 



(1) Do they subdivide? 



(2) Trace them down to their union in one large nerve, 



the sciatic. What muscles does it supply? 



(5) The Sympathetic Nerves. A small knotted nerve 



cord may be found along the side of the dorsal aorta. 



(a) Trace each nerve. 



(b) How many knots or ganglia do you find? 



(c) Use of the sympathetic nervous system? 



